PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
➤ Gửi thông báo lỗi ⚠️ Báo cáo tài liệu vi phạmNội dung chi tiết: PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
ASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekHaywardIn Partial Fulfillmentof the Requirements for the DegreeMaster of Science in Riparian Wildlife EcologyByLawrence Patrick KobernusDecember, 1998AbstractSteelhead (Oncorhynchus mykiss), a federally listed threatened species, were once common in San Lorenzo Creek, a highly modified urban stream PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekin the east San Francisco Bay Area. Since the 1940's, increased urbanization of the watershed has degraded stream habitat, and construction of dams anPKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
d flood control channels have eliminated most of the upstream habitat from steelhead access. Despite these extensive impacts, there have been occasionASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekhe fall of 1997, and isolated electroshocking surveys in 1997-98 failed to find any young steelhead in the stream system. During adult steelhead surveys in the winter and spring of 1997-98. persistent turbidity inhibited the ability to survey the stream, especially deeper pools, using either visual PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekor electroshocking methods. Exotic fishes were found to be present in San Lorenzo Creek, but two native fishes; California roach and Sacramento suckerPKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
were found to be the dominant species throughout the stream system.Evaluation of San Lorenzo Creek for steelhead habitat found limitations for the spASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekrt on Crow Creek in the winter of 1997-98. When compared to established maximum cruising (swimming) speeds for steelhead, these flood control channels were found to be virtually impassable barriers. Only very shallow depths were found where flow velocities were suitable for steelhead passage within PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekSan Lorenzo Creek concrete channel (maximum depth of 1.2 feet in channel center (e.g. V-notch)). In a section where steel baffles were placed in the VPKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
-notch to reduce velocities, maximum depth suitable for passage increased to only 1.8 feet in the channel center, and 1.0 feet along inside bends. No ASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek8 in both San Lorenzo Creek and a reference stream. San Francisquito Creek, which still retains a steelhead run. Results revealed four limitations in steelhead spawning and rearing habitat in San Lorenzo Creek: 1) few pools; 2) lack of large woody debris; 3) sedimentation of riffle habitats; and 4) PKobernus-Masters-thesis-Steelehead_san-lorenzo-creeklow abundances of benthic macroinvertebrates.Most or all of the San Lorenzo Creek sites scored below, and sometimes well below', the San FrancisquitoPKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
watershed sites for pool volume (P=0.037), pool length X average depth (P=0.018), and % pool (based on length) (P=0.037). Large woody debris was notedASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekercent fines (< 4 mm), and greater embeddedness within potential spawning gravels in San Lorenzo Creek watershed. Samples of benthic macroinvertebrates taken from two locations within each watershed showed abundances to be from 2 to 27 times lower at San Lorenzo Creek sample sites, though the highes PKobernus-Masters-thesis-Steelehead_san-lorenzo-creekt number of EPT taxa occurred at a San Lorenzo Creek site (Crow Creek).A review of water quality data collected by Alameda County Clean Water Program,PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
augmented with additional data collected in this study, found extremely high water temperatures in the San Lorenzo concrete channel during spring andASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, H PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek fall immediately downstream of the reservoirs could also impact rearing steelhead parr.Due to the adaptability of steelhead and the wandering tendency of the species, recolonization of San Lorenzo Creek is possible, yet appears highly unlikely given the current access, spawning, and rearing habitat PKobernus-Masters-thesis-Steelehead_san-lorenzo-creek limitations. Some management, restoration, and research measures are recommended for improving habitat for steelhead in San Lorenzo Creek.ASSESSMENTPKobernus-Masters-thesis-Steelehead_san-lorenzo-creek
OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDByLawrence Patrick KobernusApproved:Date:viASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, HASSESSMENT OF STEELHEAD PRESENCEAND HABITAT IN SAN LORENZO CREEK WATERSHEDA University Thesis Presented to the FacultyofCalifornia state University, HGọi ngay
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